1. People should know what the rights they're talking about are BEFORE they claim to have them and try to apply them to situations.
2. Law school ruins lives.
One of the things that really, really annoys me when I'm lurking in discussions is the freedom-of-expression card.
It annoys me for a lot of reasons, namely—
1. as far as I can tell, people using it are usually (in a New Zealand context) assuming a number of things about rights jurisprudence that aren't actually true. I think people get confused with the way the Supreme Court in the US seems to uphold their constitution all the time. We don't have a written constitution in the same way; specific to human rights, the rights are different, the court's definition of who can breach a right is different, and the court's ability to respond to breaches is different.
2. Freedom of expression in the New Zealand context (as per section 14 of the New Zealand Bill of Rights Act 1990 (BORA)) is stated simply as "Everyone has the right to freedom of expression, including the freedom to seek, receive, and impart information and opinions of any kind in any form." This is a really broad right; case law on the subject says things like "as wide a right as human thought and expression."
3. But there's more to BORA than just what the rights are. BORA only applies to acts done—
"(a) By the legislative, executive, or judicial branches of the government of New Zealand; or
(b) By any person or body in the performance of any public function, power, or duty conferred or imposed on that person or body by or pursuant to law."
(See section 3 of BORA at the link above if you don't believe me.)
That means that the right is only actionable against things done by the state. You can't enforce your section 14 freedom of expression rights against an individual you're debating with on the internet, because that individual isn't a branch of government or a person exercising public functions, duties, or powers.*
Which. Someday I'm going to actually engage in that argument with someone, saying things like "section 3 of BORA states that the Act only applies to acts done by the legislature, executive, or judiciary (or various other public sector bodies). I do not fall within that category. Therefore you have no rights under BORA as against anything I might do or say to you. I think you're thinking of the Human Rights Act, but that doesn't protect freedom of speech per se. There are protected grounds of discrimination, but your personality isn't one of them."
4. I don't think that freedom of expression, at least in the broad sense of A Thing That Is Good And Should Be Protected, stops existing because it can't be actioned or enforced in some situations. People being able to state their views openly IS a good thing, even if those views are subjectively (or objectively!) wrong.
As Voltaire said (and this gets quoted on the interwebs a LOT): "I disapprove of what you say, but I will defend to the death your right to say it."
But—if you're going to accept that (and I think we should), then you have to go back to that niggly little first word of section 14 of BORA, "Everyone", and think about that—
(a) a defence of your right to say something is not a defence of the statement itself; and
(b) if the right applies to everyone (and it must necessarily do so to be meaningful), then that must include the right to disagree; and
(c) if you are going to make public statements about something, then surely disagreement is part of the discourse; and
(d) sometimes disagreement is painful and offensive, but then sometimes the initial statements are as well.
I'm totally unconvinced by the suggestion that public disagreement with a postion taken on an issue somehow constitutes a stifling of the original statement, or an effort to shut it down, or an infringement of the original speaker's right to free speech. If anything I think that public disagreement upholds the right by validating the original speaker's right to take a position, even if it is objectionable to the respondant.
5. But I don't think that the above is necessarily what people mean when they cite their rights under BORA. Often the subtext is that you're a PC Nora-No-Friends who can't take a joke, and you want to shut them down so that we can all live in an idyllic world of sunshine and rainbows (but not the gay kind).
In which case I think the correct answer is probably to ask them why they find disagreement so hurtful and dangerous.
(There is in that last point a really interesting debate about intent, but I think at the point you're citing BORA to back up whatever you've said, you (a) are now aware that people have found it offensive, and (b) might well have known that people would find it offensive before you said it. Also I'm not willing to talk about intent and how I think it plays into debate until I've thought about it a lot, lot more.)
*Though it'd be really interesting to see what would happen if you were having a debate with, say, a Minister of the Crown online, and they tried to shut you down.